Medical radionuclide imaging, commonly referred to as nuclear medicine, is a significant diagnostic tool that involves the use of ionizing radiation to obtain accurate imaging of an in vivo patient. Typically, one or more biologically appropriate radiopharmaceuticals are administered to a patient, as by ingestion, inhalation, or injection. Tracer amounts of these radioactive substances emanate gamma quanta while localizing at specific organs, bones, or tissues of interest within the patient's body. One or more radiation detectors (e.g., positron emission tomography (PET) detector) are then used to record the internal spatial distribution of the radiopharmaceutical as it propagates from the study area. Known applications of nuclear medicine include: analysis of kidney function, imaging blood-flow and heart function, scanning lungs for respiratory performance, identification of gallbladder blockage, bone evaluation, determining the presence and/or spread of cancer, identification of bowel bleeding, evaluating brain activity, locating the presence of infection, and measuring thyroid function and activity. Hence, accurate detection is vital in such medical applications.
For accurate detection, the acquisition of timing information is critical. PET detectors rely on Constant Fraction Discriminators (CFDs) to provide accurate time determination of the arrival of an incident photon to the detector. Conventionally, CFD circuitry utilizes co-axial cables for the delay elements to allow for the necessary adjustment to obtain amplitude invariant timing for a wide range in possible detector risetimes. The use of co-axial cables and corresponding connectors introduce rather significant costs to the CFD circuitry.
Based on the foregoing, there is a clear need for an improved detector for nuclear medicine imaging.